Now that we are in the month of March, for most of us in the northern hemisphere the worst of the winter is over, and it is only a couple of weeks until 21 March, the first day of spring. 21 March is an important date for other reasons, too. For one thing, it is used as the basis for the… Continue reading The first day of spring
Tag: Earth
Why is the Sky Blue?
Explains the scientific reasons behind blue skies on Earth. It contrasts Earth's atmospheric effects with those on the Moon, where the sky appears black due to a lack of atmosphere, and Mars, where a reddish-brown hue results from iron oxide dust.
The June Solstice
The June solstice, which for most of the world will fall on June 21 this year, is the longest day in the northern hemisphere and the day when the Sun is at its highest in the midday sky (see note). The origin of the word solstice is from the Latin words sol, which means Sun, and sistere, to stand… Continue reading The June Solstice
Jun 30 2015 – Leap Second
On June 30 2015 an extra second will be inserted into the very end of the day. This extra second is called a leap second. Why do we need leap seconds? Although we take the average length of a day to be 24 hours, the mean solar day, or average "natural" day measured by the… Continue reading Jun 30 2015 – Leap Second
The Future of the Sun
The Sun, central to our Solar System, generates energy through nuclear fusion, combining hydrogen into helium. Over billions of years, it will evolve into a red giant, ultimately shedding outer layers to form a planetary nebula and becoming a white dwarf. Life on Earth will become uninhabitable well before these changes occur.
Explaining Science 